Re Updating One XL

Hi guys can someone help me with some info sometimes when I update my Tom Tom One XL Europe with Home it says it can't as there is not enough space and gives you a list of items to remove.
1st. Question is why don't Tom Tom give you the memory to able it to update.

2nd. Although you click on something to remove when it updates it puts the removed file back again ie I removed Voices and it says your device will not work properly if you removed this file (I have back up so did not worry) but it dose as the file is put back on during Update How dose this work.

3rd. As I said I have backup what I mean is a copy of the contents of my Tom Tom as if I make a Backup with Home when I go to restore it there is always an error it never restores any advice on this

4th. there are 3rd party stuff out there for my device my Question is if there is not enough space for updates how do you put extra stuff on your Device.
A big thanks to the Site its very helpful